1. Field of the Invention
The present invention relates to a method for producing glass laminates from a layered structure containing a plasticiser-containing polyvinyl acetal film and a polyvinyl acetal film with a low plasticiser content by means of fixing the polyvinyl acetal film with a low plasticiser content on the plasticiser-containing polyvinyl acetal film.
2. Background Art
In order to produce laminated glass sheets having electrically conductive structures, such as heating wires or antennas, methods are conventional in which either metal filaments are first melted onto the surface of a normal PVB film or are sewn thereinto, or the electrically conductive structures are applied to one of the glass surfaces oriented inwardly in the laminate by means of screen printing and subsequent baking. In both cases, there is the risk of economical losses if faults occur during the application to the normal PVB film or during application to a prepared glass sheet. In the first case, the PVB film can no longer be used for lamination, and in the second case the glass can no longer be used for lamination.
By contrast, the direct printing of PET films with electrically conductive structures is established in part, and for example practically invisible heating elements, sensor fields, etc. can be produced thereon. A disadvantage with an intended integration of such PET films printed with electrically conductive structures, however, is the fact that at least 3 film layers (1×functionalised PET, 2×PVB film) always have to be used, since PET cannot be melted directly on a glass surface via the functionalised side or the rear side.
Another disadvantage is the increased complexity of the film packing, which, due to the combination of the feature “with electrically conductive structures” with further functional features such as “acoustic damping”, “band filter”, “wedge-shaped thickness profile” and “shade”, leads to an increase of the complexity of the film preparation for the processor.
Similar limitations are, of course, also provided with use of PET films functionalised in other ways. For example, it may be desirable to embed, in a laminated safety glass, films that are printed decoratively or with a logo.
When producing laminated glass laminates from a plasticiser-containing polyvinyl acetal film and a polyvinyl acetal film with a low plasticiser content, an exact positioning of the films is difficult due to electrostatic charging, airflow or mechanical shifting. Furthermore, it may be desirable to introduce into a laminated glass laminate thin IR-shielding layers in the form of metal layers or layers based on nanoscale semiconductor particles in addition to one or more used PVB films.